U.S. patent application number 10/410413 was filed with the patent office on 2004-10-07 for flight control actuation system.
This patent application is currently assigned to Honeywell International Inc.. Invention is credited to Evans, Paul S., Gaines, Louie T., Kern, James I., Wingett, Paul T..
Application Number | 20040195441 10/410413 |
Document ID | / |
Family ID | 33097872 |
Filed Date | 2004-10-07 |
United States Patent
Application |
20040195441 |
Kind Code |
A1 |
Wingett, Paul T. ; et
al. |
October 7, 2004 |
FLIGHT CONTROL ACTUATION SYSTEM
Abstract
A flight control actuation system comprises a controller,
electromechanical actuator and a pneumatic actuator. During normal
operation, only the electromechanical actuator is needed to operate
a flight control surface. When the electromechanical actuator load
level exceeds 40 amps positive, the controller activates the
pneumatic actuator to offset electromechanical actuator loads to
assist the manipulation of flight control surfaces. The assistance
from the pneumatic load assist actuator enables the use of an
electromechanical actuator that is smaller in size and mass,
requires less power, needs less cooling processes, achieves high
output forces and adapts to electrical current variations. The
flight control actuation system is adapted for aircraft,
spacecraft, missiles, and other flight vehicles, especially flight
vehicles that are large in size and travel at high velocities.
Inventors: |
Wingett, Paul T.; (Mesa,
AZ) ; Gaines, Louie T.; (Phoenix, AZ) ; Evans,
Paul S.; (Mesa, AZ) ; Kern, James I.;
(Phoenix, AZ) |
Correspondence
Address: |
Honeywell International, Inc.
Law Dept. AB2
P.O. Box 2245
Morristown
NJ
07962-9806
US
|
Assignee: |
Honeywell International
Inc.
Morristown
NJ
|
Family ID: |
33097872 |
Appl. No.: |
10/410413 |
Filed: |
April 7, 2003 |
Current U.S.
Class: |
244/99.5 |
Current CPC
Class: |
B64C 13/50 20130101 |
Class at
Publication: |
244/075.00R |
International
Class: |
B64C 027/22 |
Goverment Interests
[0001] The invention described herein was made in the performance
of work under NASA Cooperative Agreement No. NCC8-115, dated Jul.
1, 1996, and is subject to the provisions of Section 305 of the
National Aeronautics and Space Act of 1958 (42 U.S.C. 2457). The
Government has certain rights in this invention.
Claims
We claim:
1. A flight control actuation system for use in a flight control
system comprising: a controller operable in response to an input
for generating a control signal; an electromechanical actuator
responsive to the control signal, for operating a flight control
surface; and a pneumatic actuator for assisting the
electromechanical actuator by reducing the load on the
electromechanical actuator.
2. The flight control actuation system of claim 1, wherein the
electromechanical actuator and the pneumatic actuator are attached
to the same flight control surface.
3. The flight control actuation system of claim 2, wherein the
flight control surface comprises at least one aileron.
4. The flight control actuation system of claim 2, wherein the
flight control surface comprises at least one flaperon.
5. The flight control actuation system of claim 2, wherein the
flight control surface comprises at least one elevator.
6. The flight control actuation system of claim 2, wherein the
flight control surface comprises at least one spoiler.
7. The flight control actuation system of claim 2, wherein the
flight control surface comprises at least one rudder.
8. The flight control actuation system of claim 1, comprising at
least one pressure vessel for supplying gas to the pneumatic
actuator.
9. The flight control actuation system of claim 1, comprising at
least one vent solenoid valve connected to the pneumatic
actuator.
10. The flight control actuation system of claim 1, comprising at
least one pressurization solenoid valve connected to the pneumatic
actuator.
11. The flight control actuation system of claim 9, comprising at
least one pressurization solenoid valve connected to the pneumatic
actuator and connected to the vent solenoid valve.
12. A flight control actuation system for use in a flight control
system comprising: a controller operable in response to an input
for generating a control signal; an electromechanical actuator
responsive to the control signal, for operating a flight control
surface; a pneumatic actuator for assisting the electromechanical
actuator by reducing the load on the electromechanical actuator;
wherein the pneumatic actuator initializes when the electrical
current in the electromechanical actuator exceeds a predetermined
amperage.
13. The flight control actuation system of claim 12, comprising at
least one vent solenoid valve and at least one pressurization
solenoid valve connected to the pneumatic actuator.
14. The flight control actuation system of claim 13, wherein the
controller closes the pressurization solenoid valve when the
electrical current decreases below the predetermined amperage.
15. The flight control actuation system of claim 12, wherein the
predetermined amperage in the electromechanical actuator is 40 amps
positive.
16. The flight control actuation system of claim 13, wherein the
predetermined amperage in the electromechanical actuator is 40 amps
positive.
17. The flight control actuation system of claim 13, wherein the
controller opens the vent solenoid valve when the electrical
current decreases below 10 amps negative.
18. A flight control actuation system for use in a flight control
system comprising: at least one aerodynamic flight control surface;
an electromechanical actuator system adapted to act on each
aerodynamic flight control surface; a pneumatic actuator system
adapted to produce a force to act on at least one of the
aerodynamic flight control surfaces; at least one electromechanical
actuator associated with a distinct one of the at least one
aerodynamic flight control surfaces; a controller adapted to
produce an electrical signal for controlling at least one of the
aerodynamic flight control surfaces; an electrical circuit
connected to the at least one electromechanical actuator with at
least one electromechanical actuator adapted to receive the
electrical signal; the pneumatic actuator system solely associated
with the at least one electromechanical actuator; the pneumatic
actuator system comprising; a piston; a pressure vessel; a vent
solenoid valve; a pressurization solenoid valve; and a pressure
switch; the vent solenoid valve and pressurization solenoid valve
adapted to receive the electrical signal to route a pneumatic
pressure; an actuation device adapted to receive the pneumatic
pressure and produce a pneumatic force; and the actuation device
being adapted to continuously actuate the distinct one of the
aerodynamic flight control surfaces of a flight vehicle in response
to the pneumatic force.
19. The flight control actuation system of claim 18, wherein a
control surface position sensor detects position information from
the aerodynamic flight control surface and sends the information to
the controller.
20. The flight control actuation system of claim 18, wherein an
electromechanical actuator position sensor detects position
information from the electromechanical actuator and sends the
information to the controller.
21. The flight control actuation system of claim 18, wherein the
stroke length of the electromechanical actuator is substantially
the same as the stroke length of the pneumatic actuator stroke
length.
22. The flight control actuation system of claim 18, wherein the
electromechanical actuator comprises a piezoelectric crystal.
23. A method for operating a flight control actuation system, the
system being adapted to activate at least one pneumatic load assist
actuator in response to at least one signal produced by a control
surface actuation signal system for positioning at least one
control surface, the method comprising the steps of: receiving an
input signal in the form of a position demand providing an
instruction for deflecting a control surface to a new position;
generating a corresponding control signal for operating an
electromechanical actuator; receiving a feedback signal in the form
of an electrical current measurement at the electromechanical
actuator; comparing the electrical current measurement to a
predetermined electrical current value; and, generating a
corresponding control signal for operating a pneumatic actuator for
reducing the load on the electromechanical actuator.
24. The method of claim 23, comprising a further step wherein the
pneumatic actuator vents and relieves force when the
electromechanical actuator tension load increases.
25. The method of claim 23, wherein the electromechanical actuator
and the pneumatic actuator are attached to the same flight control
surface.
26. A method for operating a flight control actuation system
comprising the steps of: operating a flight vehicle; receiving a
flight control surface position demand instruction; comparing the
position demand with output from a control surface position sensor;
generating an actuator position demand to at least one
electromechanical actuator; monitoring the electromechanical
actuator electrical current load; comparing the electrical current
load with a predetermined electrical current load limit; closing at
least one vent solenoid valve; opening at least one pressurization
solenoid valve whenever the electromechanical actuator current is
more than the predetermined electrical current load limit; and
closing a pressurization solenoid valve whenever the
electromechanical actuator electrical current load decreases below
the predetermined electrical current load limit.
27. The method of claim 26, further comprising the step of: opening
at least one vent solenoid valve whenever the electromechanical
actuator current is negative.
28. The method of claim 26, further comprising the step of: closing
at least one exhaust valve whenever the electromechanical actuator
current is positive.
29. The method of claim 26, further comprising the step of: opening
at least one exhaust valve and closing at least one pressurization
solenoid valve during a failure condition.
30. The method of claim 26, further comprising the step of
generating a pneumatic load assistance requirement instruction to
at least one pneumatic load assistance device, for manipulating a
flight vehicle control surface.
31. The method of claim 26, wherein the flight vehicle is an
aircraft.
32. The method of claim 26, wherein the flight vehicle is a
spacecraft.
33. The method of claim 26, wherein the flight vehicle is a
missile.
Description
BACKGROUND OF THE INVENTION
[0002] This present invention relates generally to flight control
actuation systems and, more specifically, to a method and apparatus
for a dual actuator control system, containing at least one
electromechanical actuator and at least one pneumatic actuator. The
present invention concerns actuator systems for controlling flight
control surfaces on aircraft, spacecraft, missiles, and other
flight vehicles.
[0003] Actuator servomechanism systems are used to manipulate
flight control surfaces to control flight direction, speed,
inclination and other positional adjustments for flight vehicles.
The actuator systems have used mechanical, hydraulic, electrical,
piezeoelectrical, and electromechanical systems to apply force to
the control surfaces. For safety, redundant parallel systems are
used to independently maintain control of the flight control
surface in the event of failure of one of the actuator systems. One
such parallel system is disclosed in U.S. Pat. No. 5,074,495 to
Raymond. The hydraulically- and electrically-powered actuators
individually are capable of providing full actuation power. This
system design does not account for significant variances from the
normal operational range of the electrically powered actuator, such
as control surface flutter and shockwave conditions. Flutter is
oscillatory motion between the vehicle frame and the control
surface. Flutter increases as the vehicle approaches resonant
frequencies. Shockwave conditions increase control surface loads as
the vehicle approaches sonic velocity. To account for the resultant
high control surface loads, the actuator systems must be large in
size and mass, negatively impacting flight vehicle weight
constraints and aerodynamic envelope limitations. Additionally,
large flight vehicles traveling at high speeds introduce risks of
overloading the electrical actuator from the greater forces needed
to manipulate the flight control surfaces in such situations. To
address these issues, power-assist systems were developed to
amplify the force applied from the main control system and to
minimize the control system resistance to movement. An example of
such a system is disclosed in U.S. Pat. No. 6,349,900 to Uttley, et
al. This actuator system uses an electrical actuator assisted by a
control tab mounted on the control surface. This system's drawbacks
are lower output forces than conventional actuator systems, and the
excess size and mass added to the flight vehicle from the use of
control tabs.
[0004] None of the prior art is specifically intended for
lightweight, high-speed applications, and some suffer from one or
more of the following disadvantages:
[0005] a) excessive mass and size.
[0006] b) inability to accommodate flutter or shockwave
effects.
[0007] c) increased cooling requirements.
[0008] d) low achievable output forces.
[0009] e) inferior aerodynamic envelope conditions.
[0010] f) inability to use detected electrical actuator current
variations.
[0011] As can be seen, there is a need for an improved apparatus
and method for a light, small, amplified flight control actuation
system, which reacts well to flight extremes, such as high speeds
and resonant frequencies, does not require excessive cooling,
provides high output forces and adapts to detected electrical
actuator current variations.
SUMMARY OF THE INVENTION
[0012] In one aspect of the present invention, a flight control
actuation system comprises a control means operable in response to
an input for generating a control signal, an electromechanical
actuator responsive to the control signal, for operating a flight
control surface, and a pneumatic actuator for assisting the
electromechanical actuator by reducing the load on the
electromechanical actuator.
[0013] In another aspect of the present invention, a flight control
actuation system comprises a control means operable in response to
an input for generating a control signal, an electromechanical
actuator responsive to the control signal, for operating a flight
control surface, and a pneumatic actuator for assisting the
electromechanical actuator by reducing the load on the
electromechanical actuator, wherein the pneumatic actuator
initializes when the current in the electromechanical actuator
increases beyond a predetermined amperage.
[0014] In a further aspect of the present invention, a flight
control actuation system for a flight vehicle comprises at least
one flight control surface. An electromechanical actuator system is
adapted to act on each flight control surface, and a pneumatic
actuator system is adapted to produce a force to act on at least
one of the flight control surfaces. At least one electromechanical
actuator is associated with a distinct one of the at least one
flight control surfaces and a controller adapted to produce an
electrical signal for controlling at least one of the flight
control surfaces. An electrical circuit is connected to the at
least one electromechanical actuator which is adapted to receive
the electrical signal, to control the position of the
electromechanical actuator with the electromechanical actuator
adapted to move in response to the electrical signal. The pneumatic
actuator system is solely associated with the at least one
electromechanical actuator, the pneumatic actuator system
comprising a piston, a pressure vessel, an exhaust valve, a
pressurization solenoid valve, a check valve, a manifold, a
pressure switch, the valves adapted to receive the electrical
signal and to route a pneumatic pressure to an actuation device
adapted to receive the pneumatic pressure and produce a pneumatic
force to continuously actuate the distinct one of the aerodynamic
flight control surfaces of the flight vehicle in response to the
electrical signal.
[0015] In another aspect of the present invention, a method is also
disclosed for operating a flight control actuation system, the
system being adapted to activate at least one pneumatic actuator in
response to at least one signal produced by a control surface
actuation signal system for positioning at least one control
surface. The method comprises the steps of (a) receiving an input
signal in the form of a position demand providing an instruction
for deflecting a control surface to a new position and (b) the
controller generating a corresponding control signal for operating
an electromechanical actuator. In addition the method comprises the
steps of (c) receiving a feedback signal in the form of an
electrical current measurement at the electromechanical actuator,
(d) comparing the electrical current measurement to a predetermined
electrical current value, and (e) the controller generating a
corresponding pressurization control signal for operating a
pneumatic actuator for reducing the load on the electromechanical
actuator.
[0016] In yet another aspect of the present invention, a method for
operating a flight control actuation system comprises the steps of
(a) operating a flight vehicle, (b) receiving a flap demand
instruction, and (c) comparing the position demand with output from
a control surface position sensor. In addition the method comprises
the steps of (d) generating an actuator position demand to at least
one electromechanical actuator, (e) monitoring the
electromechanical actuator electrical current load, comparing the
electrical current load with a predetermined electrical current
load limit, (f) closing at least one exhaust valve, (g) opening at
least one pressurization solenoid valve whenever the
electromechanical actuator current is more than the predetermined
electrical current load limit, and (g) closing a pressurization
solenoid valve whenever the electromechanical actuator electrical
current load decreases below the predetermined electrical current
load limit.
[0017] These and other aspects, objects, features and advantages of
the present invention, are specifically set forth in, or will
become apparent from, the following detailed description of a
preferred embodiment of the invention when read in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic of the controller-driven actuation
system acting on a flight control surface according to an
embodiment of the present invention; and
[0019] FIG. 2 is a schematic of a pneumatic actuation system
according to an embodiment of the present invention;
[0020] FIG. 3 is a perspective view of an X-33 flight vehicle with
a flight control actuation system according to an embodiment of the
present invention;
[0021] FIG. 4 is a perspective view of an electromechanical
actuator and a pneumatic actuator, both actuators acting on the
same flight control surface, according to an embodiment of the
present invention;
[0022] FIG. 5 is a graph of body flap load and body flap extension
length versus time, according to an embodiment of the present
invention;
[0023] FIG. 6 is a graph of actuator rate versus actuator force,
comparing the power demands of a sole electromechanical actuator
and the system of the present invention using an electromechanical
actuator and a pneumatic actuator, according to an embodiment of
the present invention;
[0024] FIG. 7A is a graph of a measurement of electromechanical
actuator electric current versus time, according to an embodiment
of the present invention;
[0025] FIG. 7B is a graph of body flap load moment versus time,
according to an embodiment of the present invention;
[0026] FIG. 7C is a graph of electromechanical actuator torque
versus time, according to an embodiment of the present
invention;
[0027] FIG. 7D is a graph of pneumatic actuator torque versus time,
according to an embodiment of the present invention;
[0028] FIG. 8 is a flowchart demonstrating the function and
operation of the pneumatic supply module, according to an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The following detailed description is of the best currently
contemplated modes of carrying out the invention. The description
is not to be taken in a limiting sense, but is made merely for the
purpose of illustrating the general principles of the invention,
since the scope of the invention is best defined by the appended
claims.
[0030] The present invention may comprise a position controlled
actuation system to accurately position a control surface while
using an auxiliary actuation system to provide a load trim function
for the position controlled actuation system. The present invention
may allow the use of an auxiliary actuator to provide a large
portion of the force to control the actuation system position. This
may limit the smaller portion of the load, provided by a
positioning actuator, to a level that is within the capability of a
relatively low power positioning actuator.
[0031] The invention is useful for controlling all types of flight
vehicles, including, but not limited to, aircraft, missiles
(including missile thrust vector controls), and spacecraft. One
example of a use in spacecraft is depicted in FIG. 3. The X-33
flight vehicle 250 is a one-half-scale suborbital prototype for a
proposed single-stage-to-orbit reusable launch vehicle. In flight
tests, the X-33 flight vehicle 250 will accelerate to a maximum
speed of Mach 16 and climb to an altitude of about 250,000 feet.
The X-33 flight vehicle 250 may have four types of flight control
surfaces: rudders 260, X-33 flight vehicle body flaps 270A and
270B, outboard elevons 280, and inboard elevons 290. Each of the
flight control surfaces can be independently actuated with at least
one electromechanical actuator (FIG. 1, 210A). For example, as
shown in FIG. 3, a rudder actuator 180 may be situated to operate
on rudder 260. Likewise a left outboard elevon actuator 200 may
operate on the left outboard elevon 280 and the left inboard elevon
actuator 190 may operate on the left inboard elevon 290. Left body
flap pneumatic actuator 11A and right body flap pneumatic actuator,
11B may supplement the X-33 body flap electromechanical actuator
210A and 210B forces to assist X-33 flight vehicle body flap 270A
and 270B actuation, as shown in FIG. 3. A pneumatic actuator may be
used to assist actuation of any of the flight control surfaces
available. For illustrative purposes, the following description is
of an aircraft, however, it is to be understood that other flight
vehicles can be substituted for the aircraft.
[0032] The present invention generally provides a flight control
actuation system (FIG. 1, 10) that may include an electromechanical
subsystem that can independently control a flight control surface.
The electromechanical subsystem may be associated with a pneumatic
subsystem that may assist in controlling the flight control surface
when needed. When the electrical current on the electromechanical
actuator 210A surpasses a predetermined limit, the pneumatic system
may activate under the direction of a controller. This is unlike
the prior art, which relies on redundant actuation systems of large
mass and size, which are vulnerable to flutter and shockwave
phenomena, require heavy cooling systems, are unable to respond to
electrical current load variations, produce low output forces,
negatively impact aerodynamic envelope conditions, and fail to
adjust to electromechanical overload conditions.
[0033] Referring to FIG. 1, there is shown a flight control
actuation system 10, according to the present invention, for
manipulating an aircraft flight control surface, such as an
aileron, a wing or body flap, a slat, a flaperon, an elevator, a
spoiler, or a rudder. In the present example, the flight control
surface is a body flap. The following discussion applies equally to
the left body flap (FIG. 3, 270A) and right body flap (FIG. 3,
270B).
[0034] The flight control actuation system 10 comprises a left body
flap controller 80A, which may be installed on a flight vehicle, as
shown in FIG. 3. The left body flap controller 80A may be located
within the aircraft frame. The left body flap controller 80A may be
connected to an electromechanical actuator 210A, which may be
mounted in a position to exert a force on the left body flap 270A.
The flight control actuation system 10 may operate as a
servomechanism, where left body flap controller 80A may be situated
to receive an input signal in the form of a position demand that
may provide an instruction for manipulating the left body flap
270A. The left body flap controller 80A may generate a
corresponding actuator position demand, as shown in FIG. 1, for
operating the electromechanical actuator 210A, in response to the
position demand. The left body flap controller 80A may be arranged
to receive feedback signals that indicate movement of the left body
flap 270A for generating control signals. Particularly, a control
surface position sensor 150 mounted between the aircraft body 160
and the left body flap 270A may be arranged to send electrical
signals to the left body flap controller 80A, which may indicate
the left body flap 270A position in relation to the original closed
position of left body flap 270A and the body flap acceleration.
Alternatively, an electromechanical actuator position sensor 170
may be mounted externally or internally to the electromechanical
actuator, and may be arranged to send an electrical signal
representing the left body flap 270A position and/or the linear
stroke position of the electromechanical actuator 210A to the left
body flap controller 80A. The control surface position sensor 150
and the electromechanical actuator position sensor 170 may be
rotary or linear variable differential transformers,
potentiometers, Hall effect devices, or other generally known
suitable devices.
[0035] The left body flap controller 80A may be arranged to receive
an input signal in the form of a position demand providing an
instruction for deflecting the left body flap 270A to a new
position. The position demand may be generated by a pilot, a
computer, or a remote control device. Upon receipt of the position
demand, the left body flap controller 80A may monitor the position
and acceleration signals from the control surface position sensor
150 and/or the electromechanical actuator position sensor 170 and
may generate an actuator position demand signal representing a new
stroke position for the electromechanical actuator 210A. The
response of the electromechanical actuator 210A may be to adjust
the position of the left body flap 270A by extending or retracting
the shaft to exert a force on the left body flap 270A to move the
body flap in the commanded direction. The left body flap 270A then
may move to a new position.
[0036] The behavior of the present invention can be further
understood by reference to the graph in FIG. 5, which describes the
relationship between body flap load and body flap extension length
versus time. As the load on the electromechanical actuator 210A
increases, the left body flap controller 80A may activate the
pneumatic system to cause the left body flap pneumatic actuator 11A
to act on the left body flap 270A to assist the electromechanical
actuator 210A in absorbing the load on left body flap 270A. In this
example, as the left body flap pneumatic actuator 11A initiates,
the load on the electromechanical actuator 210A may fall to values
substantially below 18,000 pounds. The load on the
electromechanical actuator 210A may peak at approximately 100,000
pounds of force, without assistance from the left body flap
pneumatic actuator 11A, which may activate during the first 100
seconds of operation. FIG. 6 demonstrates the difference between
the force requirements when using only the electromechanical
actuator 210A and using the present invention, comprising the use
of the combination of the electromechanical actuator 210A and left
body flap pneumatic actuator 11A to assist during increased flap
load conditions. The motor capability plot 240 may indicate the
capability of the electrical motor (not shown) that operates the
electromechanical actuator 210A. When the force is zero, the
maximum no-load rate point A may correspond to the maximum
attainable speed of the electrical motor. Point F represents the
maximum stall load (at zero rate), which must be resisted to hold
the flight control surface in its desired position and prevent the
surface from returning back to a neutral position (position before
extending the surface). Point B may be the maximum force condition
that combines a load that may be substantially less than the
maximum stall load F with high motor rate.
[0037] Under normal flight conditions, when the body flap load may
be low, for example, under 18,000 pounds force and 40 amps, the
left body flap pneumatic actuator 11A, attached to the left body
flap 270A, may not be in use. The body flap performance plot 230
indicates the range of power needed to operate a left body flap
270A. The ideal power condition (when using only the
electromechanical actuator 210A) may be at the body flap
specification point C. E, the body flap performance limit point,
may be the extreme condition of the body flap performance limit
point, while the intermediate point may be the location of the body
flap performance mid-point D. Using only the electromechanical
actuator 210A may not be optimal, as the majority of the body flap
performance, as represented by the length of the body flap
performance plot 230, occurs outside the capability of the motor,
as represented by the motor capability plot 240. However, when the
left body flap pneumatic actuator 11A combines with the
electromechanical actuator 210A, the electrical motor operates at
the dotted line G extending vertically down from the maximum force
condition B. The amount of force at this point, 18,000 pounds may
be the maximum electromechanical actuator force requirement to
extend the left body flap 270A, using the present invention. The
shaded portion H indicates the added capability on the left body
flap 270A with the electromechanical actuator 210A and the left
body flap pneumatic actuator 11A in combination.
[0038] FIGS. 7A, 7B, 7C, and 7D depict the electrical current
behavior in relation to the load, and actuator torques. In FIG. 7A,
the electrical current initially increases to about 40 amps, then
drops to negative values (up to about -30 amps), then level out to
values of about 0 amps. FIG. 7B shows how the load increases
substantially steadily until about the point where the electrical
current changes from positive amperage to negative amperage. The
load decreases substantially afterwards. In FIG. 7C, the torque on
the electromechanical actuator 210A exhibits behavior analogous to
the behavior of the electrical current (initially increasing,
substantially decreasing, then settling to substantially zero). In
FIG. 7D, the pneumatic torque may initially be at zero, indicating
that the left body flap pneumatic actuator 11A may not yet be
activated. When the electrical current, as shown in FIG. 7A,
reaches about 40 amps, then the left body flap controller 80A sends
a pneumatic load assistance requirement, as shown in FIG. 1. As the
left body flap pneumatic actuator 11A activates, the pneumatic
torque increases in a negative direction, as shown in FIG. 7D,
along with the increasing load shown in FIG. 7B. As the pneumatic
torque reaches a peak value (FIG. 7D), the electromechanical torque
decreases (FIG. 7C), the electrical current markedly decreases
(FIG. 7A) and the load peaks before diminishing. As can be seen by
the FIGS. 7A-7D, the combination of the left body flap pneumatic
actuator 11A with the electromechanical actuator 210A enables
effective control of the left body flap 270A while limiting the
maximum load on the electromagnetic actuator 210A with increasing
left body flap 270A loads. The controller activates left body flap
pneumatic actuator 11A when the electromechanical actuator 210A
electrical current exceeds 40 amps, to assist the manipulation of
left body flap 270A by the electromechanical actuator 210A.
[0039] In extreme flight conditions, for example high-speed flight
or large aircraft mass or size, the force needed to adjust the left
body flap 270A position may be substantial, requiring substantial
electric current to the electromechanical actuator 210A. This
normally would require an electromechanical actuator 210A of
substantial size and mass. However, using an electromechanical
actuator 210A that may be too large would affect negatively the
aerodynamic envelope. Furthermore, a massive device would
negatively affect the maximum flight weight limit and the
maneuverability of a flight vehicle. Instead, the present invention
comprises a controller that may be adapted to use a more compact,
lighter electromechanical actuator 210A. When the electrical
current load on the electromechanical actuator 210A increases past
a predetermined maximum limit, based on the capability of the
electromechanical actuator 210A, the left body flap controller 80A
may produce a signal to pressurize the left body flap pneumatic
actuator 11A, to apply force to the left body flap 270A by reducing
the load on electromechanical actuator 210A and to assist in
manipulating the position of the left body flap 270A.
[0040] FIG. 4 shows in more detail the electromechanical actuator
210A and the left body flap pneumatic actuator 11A acting on left
body flap 270A. The electromechanical actuator 210A may be operated
by an electrical motor (not shown), while the pneumatic supply
module (FIG. 2, 120) constitutes a separate pneumatic system that
powers the left body flap pneumatic actuator 11A. Using only the
electromechanical actuator 210A to manipulate the left body flap
270A would not be sufficient under conditions where the left body
flap 270A loads cause the electromechanical actuator 210A current
to exceed 40 amps. The combined effect of the force applied by the
combination of the electromechanical actuator 210A and the left
body flap pneumatic actuator 11A may act together to produce
sufficient force to manipulate the left body flap 270A even in
high-speed aircraft, missiles, or other high demand flight
vehicles. The use of the left body flap pneumatic actuator 11A may
enable the use of an electromechanical actuator 210A of low output,
with low power requirements, low mass and small size.
[0041] Referring now to FIG. 2, a schematic view of the pneumatic
portion of the flight control actuation system 10 is shown. The
pneumatic portion of the flight control actuation system 10, which
is further addressed below, may comprise one or more left body flap
pneumatic actuators 11A, one or more left body flap controllers
80A, and one or more pneumatic supply modules 120. As explained
above, the left body flap controller 80A may direct the operation
of the left body flap pneumatic actuator 11A to assist an
electromechanical actuator 210A in the manipulation of the left
body flap 270A. The left body flap pneumatic actuator 11A may
contain a left pneumatic actuator piston 20A and an actuator vent
30. The gas to provide the pneumatic force for the left body flap
pneumatic actuator 11A may be provided by the pneumatic supply
module 120 through the use of a pressure vessel 40 that stores high
pressure gas, for example, nitrogen. A manifold 100 may be coupled
to the mouth of the pressure vessel 40 for directing the flow of
pressurized gas from the pressure vessel 40 to pressurization
solenoid valves 50 which control the gas feed to the left and right
body flap pneumatic actuators 11A, 11B. Vent solenoid valves 60
control the venting of gas from the left and right body flap
pneumatic actuators 11A, 11B. At least one pressure switch 90 and
at least one check valve 110 may aid in servicing the pressure
vessel 40.
[0042] A logic flow diagram in FIG. 8 further displays the function
and operation of the pneumatic supply module 120. Left body flap
controller 80A may be connected by wires to the electromechanical
actuator 210A to determine the actuator's electric current.
Positive amperage may indicate a compressive condition in the
electromechanical actuator 210A while negative amperage may
indicate tension in the electromechanical actuator 210A. If the
electric current does not exceed the electrical current load upper
limit, for example, +40 amps, as shown in FIG. 7A, then
electromechanical actuator 210A continues to operate without
assistance from the left body flap pneumatic actuator 11A. If the
electrical current does exceed +40 amps, then the vent solenoid
valve 60 may close and the pressurization solenoid valve 50 may
open. When the electrical current falls below +40 amps, the
pressurization solenoid valve 50 may close. If the electric current
falls below the lower limit, for example, zero amps, the vent
solenoid valve 60 may open. When the electrical current rises above
the lower limit, the vent solenoid valve 60 may close. The process
shown in FIG. 8 may repeat as necessary to maintain the
electromechanical current between the upper and lower current
limits.
[0043] The pneumatic supply module 120 may comprise separate
pressurization solenoid valves 50 and vent solenoid valves 60 to
control pressure to the left and right body flap pneumatic
actuators (11A and 11B, respectively), supplied by at least one
pressure vessel 40. The pressurization solenoid valve 50 may act as
the closure valve to the pressure vessel 40, being spring-loaded
closed so as to not provide force to the left body flap pneumatic
actuator 11A or the right body flap pneumatic actuator 11B when the
system does not need assistance from the left or right body flap
pneumatic actuators 11A, 11B.
[0044] Although the present invention has been described in
considerable detail with reference to certain preferred versions
thereof, other versions are possible. Therefore, the spirit and
scope of the appended claims should not be limited to the
description of the preferred versions contained therein.
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